1. Field of the Invention
The invention in general relates to length measuring tools and more particularly to a tape rule/calculator system.
2. Statement of the Problem
Tape rules, sometimes referred to as "tape measures", are tools that are used by carpenters, mechanics, construction workers, architects, designers, real estate estimators and salespersons, and many other professionals, as well as do-it-yourselfers and almost everyone that uses tools regularly. When a tape rule is used, there is often a need to record the measurement made and calculate a desired result. Thus it is common to use a tape rule and calculator sequentially. A problem that often arises is that the person using the tape rule is in the midst of taking measurements before he or she realizes the need for the calculator, and then must interrupt the taking of measurements to get a calculator. Or, preoccupied with the taking of measurements, recording and calculating, the user may leave one tool in one location while moving to another location with the other tool. Systems are known that make it relatively easy to connect a tape measure to a belt or otherwise attach it to a persons clothing. For example, many tape rules, such as the Stanley Powerlock.TM. have a clip for attaching the tape rule to a belt or pocket. See also U.S. Pat. No. 5,025,966 issued to Stephen B. Potter. However, up to now there has been no known system for combining a tape rule and calculator. Thus there is a need for a system for including a tape rule and calculator in one package.
Even when the tape rule user has a calculator in hand, the separate units can create handling problems. While many tape rules have locks that lock the tape in place, these locks do not generally mark the place on the tape to which the measurement has been made. When making many consecutive measurements that include feet, inches, and fractions of an inch, it is easy to forget one or more portions of the measurement. It is difficult if not impossible to hold a rule in place so that a reading is not lost, and at the same time key the reading into a calculator. Thus, professionals that desire measurements to be made and recorded accurately, generally take a good deal of time carefully taking the measurement, releasing the tape, entering the measurement into a calculator or otherwise recording the figure, and then calculating the desired result. Thus a tape rule/calculator system that allows one to hold the tape with one hand while entering information into the calculator with the other would save considerable time and increase the accuracy of the measuring, recording, and calculating processes. A calculator that permits the user to record a list of measurements as well as perform calculations would be particularly useful in combination with a tape rule, since often there is a need to record measurements whether or not a calculation is to be performed.
A tape rule can often become a personal tool; that is, individuals may have strong personal preferences for a particular brand or type of tape rule. Tape rules can differ in many ways: for example, tape rules may have the numbers facing either to the left or right when the rule is extended, or aligned so they can be read vertically. Further, there are already many millions of tape rules in use. Thus it would be useful to have a tape rule/calculator system that permits a calculator to be used with the wide variety of tape rules available in the market-place and to be combined with a wide variety of conventional tape rules that are already in use. In addition, tape rules and calculators generally have different lifetimes. Thus a tape rule/calculator system that permits the tape rule and calculator to be independently replaced would be highly desirable.
The manner of using a tape rule can also be personal; that is, each individual that frequently uses a tape rule will develop habits of use that generally will be different than the habits of use of other persons. Thus there is a need for a tape rule/calculator system that is flexible enough to suit the personal habits of use of a wide variety of users.
Tape rules and calculators are often used in industrial and other work situations that can be tough on tools. Since calculators are generally not as rugged as tape rules, there is a need for a tape rule/calculator system provides protection for the calculator both while in use and while not in use.
In English speaking countries, the units of measure that are used with tape rules is generally the British foot-inch-fraction system. Calculators that use the foot-inch-fraction system are known; see for example, U.S. Pat. No. 4,488,250 issued to William S. Lipsey and Henry B. Teague. However, these calculators are all stand alone calculators. Thus it would be highly desirable to have a tape-rule/calculator system which calculates in feet, inches, and fractions.
3. Solution to the Problem
The present invention solves the above problems by providing a system for attaching a calculator to a conventional tape rule.
The invention provides a calculator case that attaches to a tape rule and a calculator that attaches to the case.
The calculator case is preferably attached to the tape rule with an elastic band. The band is made of a material, such as EPDM, that is resistant to ultraviolet light, pollutants, and abrasion, and is formed in a single-piece and is of a shape which allows it to be easily applied to any side of the tape rule and maintain a constant width to fit in a recessed channel in the case. It has an oblong cut out portion which permits the band to fit around the conventional belt clip that is attached to many tape rules. The case also includes a screw slot which allows it to be screwed to the tape rule in place of the belt clip, using the same screw that normally holds the belt clip. The screw can be used in combination with the elastic band to provide additional stability, or be used alone.
The case includes a recessed socket to receive the calculator. The calculator preferably snaps into the case pocket in one of four positions: it may be snapped into the pocket with the calculator pad facing either inward for protection or outward for use, and in each case it may take one of two orientations that differ by 180 degrees. Together with the fact that the case can be attached to any side of the tape rule, this provides at least 20 different positions in which the calculator can be mounted on a conventional tape rule to suit the preferences of the user. The case is preferably made of polyethylene which provides flexibility to allow the calculator to be easily snapped into and removed from the case. The calculator housing is made of high strength plastic, such as ABS or polycarbonate. The calculator has raised posts on the back to provide clearance from the case and thereby prevent it from sticking to the case.
The surface of calculator case that contacts the tape rule conforms to the generally convex surface of the conventional tape rule case, which permits the case to seat securely on the tape rule without wobble. The external shape and dimensions of the case also conform to the shape and dimensions of conventional tape rule cases, which makes the tape rule/calculator a single, compact, easy to handle unit, and also results in the tape rule providing protection to the calculator.
The case includes raised areas that extend beyond the calculator pocket to protect the calculator against impacts. The keypad is one-piece and rubber-sealed to keep out dust and moisture. The calculator has a lens to protect the LCD display. The calculator includes a power source that generates power from light so that it never needs batteries and thus does not have to be opened in environments that may be hostile to calculators. The calculator also may be separated from the case and used separately if needs or circumstances so warrant.
The tape rule/calculator system of the invention permits the direct input of feet, inches and fractions of inches and displays the results of calculations in these same units. Areas and volumes are calculated automatically.
The user of the tape rule/calculator system of the invention may measure a dimension while holding the tape with one hand, then, without releasing the tape rule, enter the measurement into the calculator with the other hand. The user may then perform a calculation if desired, and thereafter immediately adjust or alter the position of the tape rule and take another measurement if the circumstances warrant it. After a user acquires experience with the system according to the invention, the system effectively becomes a new tool that is much more powerful and flexible than the separate tape rules and calculators of the prior art.